OK hardly badass, but I friend wanted me to help him change out a starter motor yesterday.. Sure no problem.
I show up with my tools (never trust a friend to have the required tools!) And ask him.. "so what makes you think its the starter?".. Ummm cus it won't start.. ahh OK.
So we check all the obvious things such as corroded battery terminals flat battery etc ect.. all good then I connect a jumper from the battery post to the solenoid input on the starter and the thing fires right up... NOT the starter!
After a bit of fault finding I find the ground has dissappeared from the starter relay.. Looked like a faulty connection in the bottom of the fuse box which is all plastic welded together.
So we drilled a hole in the side of the fuse box.. bent out the ground pin on the relay to point at the hole and connected a spade terminal to a new ground wire.
Works perfectly.. cost for parts precisely $zero!..:)
He of course was on the verge of having the car towed to a mechanic!.... $$$$$
I didn't make any money but it was an interesting problem to work on..:)
Frank